R删除字符向量中的重复元素,而不是重复行

Question

我遇到了这个问题.

我有一个数据框(日期),其中一些文档ID和日期存储在一个字符向量中:

  Doc     Dates
1 12345 c("06/01/2000","08/09/2002")
2 23456 c("07/01/2000", 09/08/2003", "07/01/2000")
3 34567 c("09/06/2004", "09/06/2004", "12/30/2006")
4 45678 c("06/01/2000","08/09/2002")

我试图删除日期中的重复元素以获得此结果:

  Doc     Dates
1 12345 c("06/01/2000","08/09/2002")
2 23456 c("07/01/2000", 09/08/2003")
3 34567 c("09/06/2004", "12/30/2006")
4 45678 c("06/01/2000","08/09/2002")

我试过了:

R>unique(dates$dates)

但它会按日期删除重复的行:

  Doc     Dates
1 12345 c("06/01/2000","08/09/2002")
2 23456 c("07/01/2000", 09/08/2003")
3 34567 c("09/06/2004", "12/30/2006")

有关如何仅删除日期中重复元素的任何帮助,而不是按日期删除重复行？

**更新了数据

# Match some text string (dates) from some text:

df1$dates <- as.character(strapply(df1[[2]], "((\\D\\d{1,2}(/|-)\\d{1,2}(/|-)\\d{2,4})|    ([^/]\\d{1,2}(/|-)\\d{2,4})|((JAN|FEB|MAR|APR|MAY|JUN|JUL|AUG|SEP|OCT|NOV){1}[\\s|-]{0,2}\\d{1,4}(\\D[\\s|-]{0,}\\d{2,4}){0,}))"))

# Drop first 2 columns from dataframe
df2<-df1[ -c(1,2)]

# List data
>df2
872                     7/23/2007
873 c(" 11/4/2007", " 11/4/2007")
874   c(" 4/2/2008", " 8/2/2007")
880                    11/14/2006

> class(df2)
[1] "data.frame"

> class(df2$dates)
[1] "character"

> dput(df2)
structure(list(dates = c("NULL", "NULL", " 7/23/2007", "c(\" 11/4/2007\", \" 11/4/2007\")", 
"c(\" 4/2/2008\", \" 8/2/2007\")", "NULL", "NULL", "NULL", "NULL", 
"NULL", " 11/14/2006")), .Names = "dates", class = "data.frame", row.names = 870:880)

所以我的问题是如何摆脱第873行的重复日期？

Answer 1

尝试这个：

within(dates, Dates <- lapply(Dates, unique))